Package org.apache.catalina.tribes

Interface ChannelInterceptor

All Superinterfaces:
Heartbeat, MembershipListener
All Known Implementing Classes:
ChannelCoordinator, ChannelInterceptorBase, DomainFilterInterceptor, EncryptInterceptor, FragmentationInterceptor, GroupChannel, GzipInterceptor, MessageDispatchInterceptor, NonBlockingCoordinator, OrderInterceptor, SimpleCoordinator, StaticMembershipInterceptor, TcpFailureDetector, TcpPingInterceptor, ThroughputInterceptor, TwoPhaseCommitInterceptor
public interface ChannelInterceptor extends MembershipListener, Heartbeat
A ChannelInterceptor is an interceptor that intercepts messages and membership messages in the channel stack. This allows interceptors to modify the message or perform other actions when a message is sent or received.

Interceptors are tied together in a linked list.

See Also:

  • Method Details

    • getOptionFlag

      int getOptionFlag()
      An interceptor can react to a message based on a set bit on the message options. When a message is sent, the options can be retrieved from ChannelMessage.getOptions() and if the bit is set, this interceptor will react to it.

      A simple evaluation if an interceptor should react to the message would be:
      boolean react = (getOptionFlag() == (getOptionFlag() & ChannelMessage.getOptions()));
      The default option is 0, meaning there is no way for the application to trigger the interceptor. The interceptor itself will decide.

      Returns:
      int
      See Also:

    • setOptionFlag

      void setOptionFlag(int flag)
      Sets the option flag
      Parameters:
      flag - int
      See Also:

    • setNext

      void setNext(ChannelInterceptor next)
      Set the next interceptor in the list of interceptors
      Parameters:
      next - ChannelInterceptor

    • getNext

      ChannelInterceptor getNext()
      Retrieve the next interceptor in the list
      Returns:
      ChannelInterceptor - returns the next interceptor in the list or null if no more interceptors exist

    • setPrevious

      void setPrevious(ChannelInterceptor previous)
      Set the previous interceptor in the list
      Parameters:
      previous - ChannelInterceptor

    • getPrevious

      ChannelInterceptor getPrevious()
      Retrieve the previous interceptor in the list
      Returns:
      ChannelInterceptor - returns the previous interceptor in the list or null if no more interceptors exist

    • sendMessage

      void sendMessage(Member[] destination, ChannelMessage msg, InterceptorPayload payload) throws ChannelException
      The sendMessage method is called when a message is being sent to one more destinations. The interceptor can modify any of the parameters and then pass on the message down the stack by invoking getNext().sendMessage(destination,msg,payload).

      Alternatively the interceptor can stop the message from being sent by not invoking getNext().sendMessage(destination,msg,payload).

      If the message is to be sent asynchronous the application can be notified of completion and errors by passing in an error handler attached to a payload object.

      The ChannelMessage.getAddress contains Channel.getLocalMember, and can be overwritten to simulate a message sent from another node.

      Parameters:
      destination - Member[] - the destination for this message
      msg - ChannelMessage - the message to be sent
      payload - InterceptorPayload - the payload, carrying an error handler and future useful data, can be null
      Throws:
      ChannelException - if a serialization error happens.
      See Also:

    • messageReceived

      void messageReceived(ChannelMessage data)
      The messageReceived is invoked when a message is received. ChannelMessage.getAddress() is the sender, or the reply-to address if it has been overwritten.
      Parameters:
      data - ChannelMessage

    • heartbeat

      void heartbeat()
      The heartbeat() method gets invoked periodically to allow interceptors to clean up resources, time out object and perform actions that are unrelated to sending/receiving data.
      Specified by:
      heartbeat in interface Heartbeat

    • hasMembers

      boolean hasMembers()
      Intercepts the Channel.hasMembers() method
      Returns:
      boolean - if the channel has members in its membership group
      See Also:

    • getMembers

      Member[] getMembers()
      Intercepts the Channel.getMembers() method
      Returns:
      the members
      See Also:

    • getLocalMember

      Member getLocalMember(boolean incAliveTime)
      Intercepts the Channel.getLocalMember(boolean) method
      Parameters:
      incAliveTime - boolean
      Returns:
      the member that represents this node
      See Also:

    • getMember

      Member getMember(Member mbr)
      Intercepts the Channel.getMember(Member) method
      Parameters:
      mbr - Member
      Returns:
      Member - the actual member information, including stay alive
      See Also:

    • start

      void start(int svc) throws ChannelException
      Starts up the channel. This can be called multiple times for individual services to start The svc parameter can be the logical or value of any constants
      Parameters:
      svc - one of:
      • Channel.DEFAULT - will start all services
      • Channel.MBR_RX_SEQ - starts the membership receiver
      • Channel.MBR_TX_SEQ - starts the membership broadcaster
      • Channel.SND_TX_SEQ - starts the replication transmitter
      • Channel.SND_RX_SEQ - starts the replication receiver
      Throws:
      ChannelException - if a startup error occurs or the service is already started.
      See Also:

    • stop

      void stop(int svc) throws ChannelException
      Shuts down the channel. This can be called multiple times for individual services to shutdown The svc parameter can be the logical or value of any constants
      Parameters:
      svc - one of:
      • Channel.DEFAULT - will shutdown all services
      • Channel.MBR_RX_SEQ - stops the membership receiver
      • Channel.MBR_TX_SEQ - stops the membership broadcaster
      • Channel.SND_TX_SEQ - stops the replication transmitter
      • Channel.SND_RX_SEQ - stops the replication receiver
      Throws:
      ChannelException - if a startup error occurs or the service is already started.
      See Also:

    • fireInterceptorEvent

      void fireInterceptorEvent(ChannelInterceptor.InterceptorEvent event)
      Fire an event.
      Parameters:
      event - the event

    • getChannel

      Channel getChannel()
      Return the channel that is related to this interceptor
      Returns:
      Channel

    • setChannel

      void setChannel(Channel channel)
      Set the channel that is related to this interceptor
      Parameters:
      channel - The channel